The Sontaran StrategemThe Poison Sky Novelisation
by Josman
Summary: The Doctor and Donna reunite with Martha, now working for UNIT. They join the organisation investigating a covert operation to destroy the human race by taking control of their cars.
1. A New UNIT

**Author's Notes: My status of Doctor Who non ownership should be well established by now.**

**The Sontaran Stratagem**

**Chapter 1: A New UNIT**

From the outside, The Rattigan Academy looked like any other high class boarding school, with a large stone building, surrounded by extensive grounds and tennis courts. A look inside would have told you that it was something else entirely. But no visitor was yet to discover the full scale of the weirdness. Even the students were unaware of it.

Anyone casually walking through the grounds tonight might have been concerned by the gang of teenagers in red hoodies dragging a protesting woman out to the car park and pushing her down the steps, before a differently dressed kid, several inches shorter than the others stepped forward and tossed her folder after her, scattering her notes everywhere.

"I think that makes my answer perfectly clear." He smiled. "Oh, and if you go to print, make sure to spell my name right. Luke Rattigan, with two Ts."

Jo Nakashima hurriedly gathered up her notes and stood up. "Oh this goes way beyond the papers! This is worldwide. ATMOS is dangerous!"

"If you had proof, you wouldn't be here!" Rattigan snapped.

"Fine. If you won't listen to me, I'll find someone who will!" She got in her car and started the engine.

"_ATMOS online._"

"Deactivate." She said to the voice commands speaker.

"_ATMOS cannot be disabled._"

"Fine." She sighed. "Take me to UNIT headquarters. Tower of London."

* * *

In his lavish private quarters, Luke was idly bouncing a squash ball on his racket as he talked to his associates via video link. He never played squash of course, but he kept the equipment for irritating visitors.

"Her name's Jo Nakashima." He said. "Freelance journalist. Clever by the sounds of it. Not as clever as me, but that goes without saying. Recommend she be terminated."

"Remember your status, boy. We do not take orders from humans."

"I said _recommend_."

"Very well then. Your advice shows military wisdom. She will be dealt with."

"Cool." He shrugged.

* * *

Jo Nakashima's introduction to alien life had been the same as every other freelance journalist UNIT unofficially had working for them. Namely stumbling upon them by pure chance whilst investigating something else. In her case, she'd been to interview a research establishment that was suspected of performing illegal experiments on cats and "accidentally" taken a wrong turning so she could find something to expose them first hand. As it turned out, the cats were actually a super intelligent feline alien species who were conducting illegal experiments on the scientists. Thanks to her, UNIT had been able to put a stop to things. The experience had opened her mind to what other bizarre phenomena were lurking in plain sight and she'd instinctively sought out these sorts of stories.

Whilst UNIT wouldn't admit it, the freelance journalists were their main source of leads. Whilst it was possible for a shady research organisation to hide behind layers of bureaucracy when it came to officials. Freelance journalists took pride in their ability to sneak around these barriers. The only problem was getting UNIT to answer the phone.

"_You have reached UNIT extension 251_." Said the automated voice on the phone. "_Please leave a message after the tone._"

"Yes, this is a message to Colonel Mace from Jo. Jo Nakashima. Look, you should have got my email. I've been investigating a number of deaths related to ATMOS systems."

"_Go straight on._" Said the satnav, taking her over a bridge.

"Now, I can't prove anything, but there's got to be a link. I need you to check out all the people who died in ATMOS cars yesterday, and then check out the time."

"_Turn right._" Said the satnav.

Jo obediently turned right, but found herself on waste ground, facing a river. "I don't believe this." She said.

"_This is your final destination._"

"I said take me to UNIT."

"_This is your final destination._"

"Fine then. I'll find my own way there." She reached over to put the car in reverse, only for the gear lever to swing away from her hand and into first. When she tried to pull it back, it wouldn't budge. At the same time, all the doors locked.

"_This is your final destination._"

The throttle slammed down and the car shot forward. Joe pressed down on the brake, but nothing happened. The steering wheel wouldn't turn either. She tried the handbrake, the clutch and just turning the keys, but nothing responded.

"NOOOOOOOOOOO!" She screamed as she plunged into the river.

* * *

The Doctor had set the TARDIS console to basic settings so Donna could have a go, as well as modifying the panel next to the panel next to her to act as an instructor's panel, with the necessary temporal dampers he could pull to override her. Against all expectations, she'd gone almost three minutes without him needing to.

"I can't believe I'm doing it!" She grinned.

"No. Nor can I." He nodded. "Ooh, left hand down, left hand down." Donna grabbed the lever the Doctor had said was called the lateral... thinganiser or something. The Doctor, meanwhile, had noticed something alarming on the readouts and grabbed the brake. When it proved too stiff, he whacked it with the rubber mallet. "Getting too close to the 1980s."

"What am I gonna do? Put a dent in 'em?"

"Well… Someone has."

An electronic ringing sounded through the console room. The Doctor pressed some buttons to put the TARDIS back into neutral.

"Hold on." Said Donna. "That's a phone. What's a phone doing on a spaceship?"

The Doctor pressed a button and a phone popped out of a little tube on the side of the console. "It's not mine." He answered it. "Hello."

"Doctor!" Said Martha's voice. "It's me. And I'm bringing you back to Earth."

* * *

Martha stood in an alleyway between two outbuildings, awaiting that sound that had spirited her off to adventure what felt like a lifetime ago. She'd been a different person then. Younger, more innocent. Though she'd put that traveling behind her, she hadn't stopped trying to make a difference in the world. Now, finally, it was time for a reunion.

The TARDIS faded into view and the Doctor stepped out. For a moment, the two stood looking at each other, then ran up and hugged. "Martha Jones." The Doctor grinned. "How's the family?"

"They're alright. Recovering."

"And you?"

Before Martha could answer, she spotted someone else following him out. "Right. Should've known. Didn't take you long to replace me."

"Just don't start fighting." The Doctor said quickly, remembering what had happened with Rose and Sarah Jane. "Martha, Donna. Donna, Martha." And don't fight. I can't stand fighting."

"You wish." Donna snorted, and shook Martha's hand warmly. "Hi, you must be Martha. He talks about you all the time."

"I dread to think." Said Martha.

"No. Good things. Nice things. He's told me all about you."

"Oh… All of it?"

"Didn't take you long to get over it though. Who's the lucky man?"

"What?" Said the Doctor. "What man?"

"She's engaged you dumbo." Donna pointed to the ring on Martha's finger.

"Realy? Who to?"

"Tom. That Tom Milligan. He's in paediatrics. Working out in Africa right now. And yes, I know, I've got a doctor who disappears off to distant places. Tell me about it."

"Is he skinny?" Said Donna.

"No. He's, sort of, strong."

Donna nodded to the Doctor. "He, is too skinny for words. You try to hug him. You get a paper cut." They laughed together.

"I preferred it when you were fighting." Said the Doctor.

At this point, a radio in Martha's jacket began to squawk. "Speaking of which…" She picked up the radio. "This is Martha Jones. Operation Blue Sky is go go go. Repeat, we have a go."

Seconds later, a convoy of army land rovers came cruising down the quiet road, flanked by soldiers. "UNified Intelligence Taskforce!" Shouted a man with a megaphone. "Raise that gate now!"

The soldiers charged through into the courtyard at the front of what appeared to be an ordinary factory, where workers in overalls turned to stare at the soldiers.

"Leave those safeties on, lads. They're non-hostiles." Announced the man with the megaphone, before turning back to the workers. "All workers, lay down your tools and surrender."

"Greyhound Six to Trap One. B Section, go, go, go. Search the ground floor. Grid pattern delta." Martha said into her radio, as she rushed forward to join them.

"What are you searching for?" Said the Doctor.

"Illegal aliens. B section mobilised. E section, F section, on my command."

The soldiers swarmed among the factory workers, grabbing them roughly and standing them at gunpoint against the wall.

Donna, meanwhile, was looking stunned. "Is that what you did to her? Turned her into a soldier?"

* * *

"Just as we predicted. The UNIT troops are mobilising."

The commander tapped the surveillance feed they were looking at. "Observe their soldiers. Their primitive weapons, exposed skin, feeble armour. These are toy soldiers. The playthings of children."

* * *

With everything underway, Martha returned to the Doctor, who got a good look at her name badge for the first time. "And you're a proper Doctor now?"

"UNIT rushed it through." She grinned. "Given my experience in the field. Come on. They're establishing a base on sight. They're dying to meet you."

"Wish I could say the same."  
A black lorry had followed the land rovers into the factory and parked out front. Its side extended outwards like one of those American RVs. This, apparently, was UNIT's mobile headquarters.

Inside, was a medium sized control room, with technicians and officers working on a variety of screens. On a bank behind them, a man in Colonel's uniform was overseeing everything.

"Operation blue sky complete sir." Said Martha. "Thanks for letting me take the lead. And this is the Doctor. Doctor, Colonel Mace."

"Doctor." Mace saluted.

"Oh, don't salute." Said the Doctor.

"But it's an honour sir. I've read all your files. Technically speaking, you're still on staff. You never resigned."

"What, you used to work for them?" Said Donna.

"Yeah, back in the 70s… Or was it the 80s?" Said the Doctor. "But it was all a bit more home spun back then."

"Times have changed sir." Said Mace.

"That's enough of the sir."

"But you've seen it Doctor." Said Martha. "You've been on board the Valliant. We've got massive funding from the United Nations. All in the name of home world security"

"A modern UNIT for a modern world." The Colonel said proudly.

"What, and that means arresting ordinary factory workers, in the streets, in broad daylight?" Donna cut in. "It's more like Guantanamo Bay out there. Donna, by the way. Donna Noble, since you didn't ask. I'll have a salute."

The Colonel looked at the Doctor, who nodded. He promptly saluted Donna.

The Doctor decided to move on. "Tell me, what's going on in that factory?"

The Colonel brought up a map of the world on the big screen. "Yesterday, fifty two people died in identical circumstances, right across the world, in eleven different time zones. Five a.m. in the UK, six a.m. in France, eight a.m. in Moscow, one p.m. in China."

"You mean they died simultaneously?"

"Exactly. Fifty two deaths at the exact same moment, worldwide."

"How did they die?"

"They were all inside their cars."

"They were poisoned. I checked the biopsies. No toxins. Whatever it is, left the system immediately." Said Martha.

"What have the cars got in common?" Said The Doctor.

"Completely different makes. They're all fitted with ATMOS, and that is the ATMOS factory."

"What's ATMOS?"

"Oh, come on!" Donna laughed, pleased to know something the Doctor didn't. "Even I know that. Everyone's got ATMOS."

* * *

Deciding that showing him would be quicker, they led him through the crowds of soldiers in the factory.

"Stands for ATMospheric Omissions System." Said Martha. "You install it in your car. It reduces the Co2 emmisions to zero."

"Zero?" Said the Doctor. "No carbon at all?"

"Plus you get satnav thrown in, plus 20 quid in shopping vouchers if you introduce a friend." Said Donna. "Bargain."

"And this is the factory where it's made and shipped worldwide." Said Mace.

"And you think ATMOS is alien?" Said the Doctor.

"That's what we need you to find out."

They found a testing room, full of equipment for aiding the researchers. "Here it is, laid bare." Said the Colonel.

"You must have checked it before it went on sale?" Said the Doctor.

"We did. Found nothing." Said Martha. "That's why I said we needed an expert."

"Really? Who'd you get?" The Doctor realised they were all staring at him. "Oh me! Right." He pulled on his glasses to have a better look at the equipment. Martha and Mace decided to leave him to it.

"So why would aliens be so keen on cleaning up our air?" Said Donna. "Maybe they want to help?"

"Donna." He said seriously. "Do you know how many cars there are on Earth? 800 million. Control them and you have 800 million weapons."

* * *

For Private Harris, the army had been a very disappointing experience. He'd grown up watching exciting action films. Smash into the bad guys' lair, shoot 'em full of lead, grab the girl, smash out through the window, blow up the building for good measure. But proper military duty had largely consisted of patrolling armouries no one had tried to break into for years and parading on special events. Even in his one tour of Afghanistan, the Taliban had been irritatingly quiet.

That had all changed when the ghosts lining the streets had transformed into Cybermen and his men had found themselves in a fight for their lives. Most of the others were traumatised but he was delighted. This was exactly what he'd signed up for. He was even happier to discover that there was an organisation that did this sort of things all the time. Of course the recruitment officers had reminded him of the dangers several times, but he hadn't cared.

His friend, Private Grey, had accompanied him along. He was less excited by the prospect of meeting those aliens again, more by the list of privileges awarded to UNIT soldiers.

As the lights came on in the service tunnels beneath the building, Grey had a look at the schematics. "We should head back. There's not much down here. Just boiler rooms, generators."

"Aye ay, what's this then?" Said Harris. Down a side corridor, two factory workers were flanking a steel door. "You two, all personnel have been ordered to evacuate. This building's under UNIT control."

"This area is out of bounds." Said one of the workers.

"Excuse me, sunshine? I think you'll find we're in charge! We can do this the easy way, or the hard way."

"General Staal, they are close."

"Excellent. Like a good warrior, I shall enter the fray myself. Let them pass."

The guards hit a button and the door slid open. "It's open."

"Ah. Thank you very much." Harris grinned.

The room on the far side was filled with vats and equipment far beyond their understanding.

"Greyhound Sixteen to Trap One. We've found something. Basement corridor, north side, grid thirty six. Request backup, over." Grey said into his radio. But they seemed to be busy.

Harris had what appeared to be a covered metal bath in the centre of the roof and held his ear above it. "There's something boiling in there."

"Don't touch it!" Said Grey.

"Come on Steve! We get first rights on this. That means promotion."

"I just think we should wait for backup."

A bang punctuated the air.

"What was that?" Said Grey.

"It came from inside."

"It could just be the machinery."

The lid banged twice more.

"Is there someone in there?" Shouted Harris, as the box banged again. He banged twice on the lid himself. The lid banged back twice. "We've got to get it open!"

"We should wait for the others!"

"It could suffocate in there!" He hammered on some buttons on the side.

Grey got back on the radio. "Greyhound Sixteen to Trap One, request immediate assistance. Repeat, immediate assistance, over."

"How do you work this thing? Come on." Muttered Harris. Finally, he hit the right button and the lid lifted open, revealing a large pool of opaque green liquid, with the consistency of fabric softener and the smell of rotten fish. "What on Earth is that stuff?"

Abruptly, a pale naked body rose from the pool, but its face was round and featureless. Its eyes, if it had any were fused shut. It tried to open its mouth, but still stray bits of flesh linked the two lips together.

Grey levelled his rifle at it. "Identify yourself! Identify! Greyhound Sixteen declaring Absolute emergency, sir. Repeat, Absolute emergency. Over."

Harris, meanwhile, bent down to the creature. "Can you hear me? Can you understand me? Look at its neck. Looks like an umbilical cord."

"Don't get too close!"

"I think it's harmless."

The creature slid back down and under the fluid.

"It's gonna drown!" Said Grey.

"No. I think it breathes that stuff."

"An excellent deduction." Said a new voice. "I would rate you above average, soldier. Well done. Whereas you, you smell of sweat and fear."

The soldiers swung round to point their guns at a squat figure in blue armour. Its round helmet, with the red eye slits made it look a little bit like a child's toy. They also noticed it had three fingers on each hand.

Harris lowered his gun and laughed. "Yeah? Well we're not the ones who got out of school early sunshine. Now stop playing Humpty Dumpty and tell us who you are."

"Is that a reference to my height?"

"Short answer… Yeah!"

"A pity. Words are the weapons of womenfolk. I must judge you unfit."

"What're you gonna do? Bite our ankles?"

The figure pulled out a metallic wand and zapped Harris's ankles. He promptly collapsed, screaming.

"I'm warning you!" Shouted Grey, brandishing his gun.

"A proper soldier gives no warning. He shoots. Fire. I order you. Fire!"

Grey pulled the trigger. The gun clicked in his hands. He flicked several of the catches. Same result. His pistol wouldn't work either.

"The room is contained within a cordolaine signal, exciting the copper surface of the bullet and causing expansion within the barrel, rendering your guns useless. And your radio signals have been blocked."

Grey roared and charged forward, raising his rifle to club the figure. It promptly zapped his ankles too.

"My legs." Grey gasped. "I can't feel my legs!"

"I apologise for disabling you. Death has more honour. But you are needed for the stratagem. Prepare them for processing. You spoke of promotion. Now you will serve a greater cause."

The soldiers screamed for help as two factory workers emerged to drag them away. But they were too far away to be heard. "Who are you?" Said Harris.

"Indeed, know your enemy. I am General Staal of the Tenth Sontaran Battle Fleet. Known as Staal the Undefeated."

When he removed his helmet, the soldiers screamed all the harder.


	2. Homecoming

**Chapter 2: Homecoming**

The Doctor peered at an ATMOS device and exhaust pipe which had been specially made of clear plastic so the experts could see it working more thoroughly. "Ionising nano-membrane carbon dioxide converter. Which means that ATMOS works. Filters the CO2 at a molecular level."

"Yes, we know all that." Said the Colonel. "Is it alien."

The Doctor pondered that question. "No. Decades ahead of its time." He looked at the Colonel, stood next to him. "Do you mind? Could you stand back a bit?"

"Sorry, have I done something wrong?"

"You're carrying a gun. I don't like people with guns."

Mace frowned. "If you insist." He said tactfully, and left.

"Tetchy." Said Martha.

"It's true though."

"He's a good man!"

"People with guns are usually the enemy. You seem quite at home."

Martha knew the Doctor had a low opinion of military people. He never had. They represented rigid unquestioning authoritarianism and over reliance on brute force. She suspected his part in the time war had deepened his wish to distance himself from the military. She needed to gently remind him that they both had similar aims, to stand up for what they believed in and go to any lengths to save the people they loved. "If anyone got me used to fighting it's you."

"Oh, so this is all my fault?"

"Well you got me the job! Besides, look at me, am I carrying a gun?"

He looked her over. "I suppose not."

"It's all right for you. You can just come and go, but some of us have got to stay behind. So I've got to work from the inside, and by staying inside, maybe I stand a chance of making them better."

The Doctor smiled. "That's a bit more like Martha Jones. Saving the Earth."

"I learnt from the best." She grinned.

"Oi you lot." Donna stepped in from a file room. "All your storm troopers and your sonics. You should of come with me."

"Why, where have you been?" The Colonel returned at the sound of her statement.

"Personnel. That's where the weird stuff's happening, in the paperwork. Because I spent years working as a temp, I can find my way round an office blindfold, and the first thing I noticed is an empty file."

"Why? What's inside it?" Said the Doctor. "Or what's not inside it?"

"Sick days. There aren't any. Hundreds of people working here and no one's sick. Not one hangover, man flu, sneaky little shopping trip, nothing. Not ever. They don't get ill."

"That can't be right." Said the Colonel.

"You've been checking the buildings. You should of looked at the workforce."

"I can see why he likes you." Martha grinned.

"Super temp!"

"Doctor Jones. Set up a medical post and start examining the workforce. I'll send them through." Said the Colonel.

"Yes sir. Donna, you can give me a hand."

As they went to get on with it, the Doctor decided to try a more civil tone with the Colonel. "So this ATMOS stuff, where did it come from?"

"Luke Rattigan himself."

"And himself would be?"

* * *

The Colonel took the Doctor back to headquarters to show the Doctor Rattigan's online profiles. "Child genius. Invented the Fountain Six search engine when he was twelve years old. Millionaire overnight. Now runs the Rattigan Academy. A private school, educating students handpicked from all over the world."

"A school for geniuses. I wouldn't mind going there… I get lonely."

The Colonel chose to believe that wasn't meant offensively.

* * *

"Do you think I should warn my mother, about the ATMOS in her car?" Said Donna.

"Better safe than sorry." Said Martha.

"I should give her a call."

Martha thought about this girl. She wasn't sure how long she'd been traveling for, but she guessed it wasn't long. She wouldn't know just how simultaneously wonderful and terrible adventures in the TARDIS could be. "Donna… Do your family know where you are? That you're traveling with the Doctor, I mean?"

"Not really. Although my granddad sort of waved us off. I didn't have time to explain."

"You left him behind?"

"Yeah."

"I didn't tell my family. I kept it all so secret, and it almost destroyed them." Said Martha.

"In what way?"

"They ended up imprisoned. They were tortured. My Mum, my Dad, my sister." Donna's eyes had gone wide. "It wasn't the Doctor's fault, but you need to be careful. Because you know the Doctor. He's wonderful, he's brilliant, but he's like fire. Stand too close and people get burnt."

* * *

Grey and Harris emerged from the underground lab, now wearing the same blank expression the guards had.

"Conditioning is complete." Said Staal. "Now begin your duties and advance the conquest."

"Yes sir." They said.

"General Staal returning." He said into his radio. "The stratagem advances. The last days of planet Earth."

* * *

"You're not coming with me." The Doctor said. "I want to talk to this Luke Rattigan. Not point a gun at him."

Mace wasn't impressed by what he'd seen so far. His predecessors had warned him that the Doctor was a brilliant man, but he was also mad and very difficult to work with. He was starting to see their point. "It's 20 miles outside of London."

"Then get me a jeep." Said the Doctor.

"Our records show you travel by TARDIS."

"Yes, but in a battle situation, I prefer to keep the super duper time machine off the front lines."

"I see, then you do have weapons but you choose to keep them hidden." He turned to a soldier stood by a jeep. "Jenkins."

"Sir." Said Jenkins.

"You will accompany the Doctor and take orders from him."

"Yeah, I don't do orders." Said the Doctor.

"Any sign or trouble, get Jenkins to declare a code red. Good luck sir." Mace saluted again.

"I said no salutes."

"Now you're giving orders." The Colonel turned away.

"Oh, you're getting a bit cheeky, you are."

"Doctor…" Donna emerged from the building.

"Oh, just in time!" The Doctor grinned. "Come on, come on, we're going to the country. Fresh air and geniuses, what more could you ask?"

"I'm not coming with you. I've been thinking. I'm sorry, I'm going home."

"Really?" Said the stunned Doctor.

"I've got to."

The Doctor sighed. "Oh, if that's what you want. I mean, it's a bit soon. I had so many places I had wanted to take you. The Fifteenth Broken Moon of the Medusa Cascade, the Lightning Skies of Cotter Palluni's World, Diamond Coral Reefs of Kataa Flo Ko. Thank you. Thank you, Donna Noble, it's been brilliant. You've, you've saved my life in so many ways. You're… you're just popping home for a visit, that's what you mean."

Donna had been thinking of interrupting him, but as his sad farewell speech went on, it had just got too hilarious to put a stop to. "You dumbo."

"And then you're coming back."

"You know what you are? Great big outer space dumbo."

"Ready when you are sir." Jenkins leaned through the window.

"What's more, you can give me a lift. Come on." Donna followed the Doctor to the passenger side door. "Broken moon of what?"

"I know, I know." The Doctor grinned.

* * *

Having donned her lab coat and stethoscope, Martha took a look at the first worker the Colonel had sent through. "And your name's Trepper, yeah? Is that Polish? Listen, we're not checking passports. It's not about that. But did you come across from Poland just to work?"

"I came here to do my job." He said in a monotonic voice.

"Okay. I need to listen to your heartbeat. This might be a bit cold. Lift."

Trepper obediently lifted his shirt up, to reveal a hairless chest. Martha placed the stethoscope over his heart and heard a beat like a jackhammer.

"Mr Trepper are you under any kind of medication or hypnosis."

"I'm here to work." He said again.

"And how many hours a day do you work?"

"24."

"You work 24 hours a day?" At this point, it occurred to her that Trepper still held his shirt up. "Down." He immediately dropped it. She'd also observed that he was staring blankly forward and had hardly blinked since she'd led him in. Looking at the others lined up outside, she saw similar symptoms in them. That told her all she needed to know. "Wait here for a bit."

As she left the room, however, she was approached by two privates. "Doctor Jones?"

"Can it wait? I'm a bit busy."

"Do you have level one clearance?"

"Yeah, why?"

"Colonel Mace wants to see you."

That got her attention. "Good, 'cos I want to see him. Where is he?"

"Follow us." Grey and Harris led her away.

* * *

Jackson dropped Donna off at the end of her road, with the promise to pick her up on the way back.

It was bizarre revisiting home. The quiet suburban road with its neatly kept front gardens and kids playing football was a far cry from the cobbled streets of Pompeii or the snowy landscapes of the Ood world.

It only now occurred to her how close she'd come to never seeing home again. Just in the last few days, she'd been trapped in Mount Vesuvius, dangled off a high building and tied down for human sacrifice. Only to name a few. And no one here could begin to understand everything she'd seen. Except perhaps…

Up ahead, her Granddad was retrieving the dustbin from the kerb. He spotted her approaching and clapped his hands over his mouth.

Overcome by everything, she ran up and hugged him.

"It's aliens, I said so!" Wilf smiled as he got out some biscuits. "I just didn't expect them to come in a little blue box."

"It's bigger on the inside." Said Donna.

"But is it safe though? Are you safe with him?"

"He's amazing, Gramps. He's just dazzling. And never tell him I said that."

"No." He agreed.

"But I'd trust him with my life."

"Hold up, I thought that was my job."

"You still come first."

"Well, whatever you do, don't tell your mother." While he was pleased to see Donna out having adventures, he didn't think Sylvia would be so pleased. She'd be afraid of losing the girl, especially after losing her husband so recently

"I don't know. I mean, this is massive. Sort of not fair if she doesn't know."

"Doesn't know what?" Sylvia entered with an armful of dirty clothes. "And who's she, the cat's mother? And where've you been these past few days, lady, after that silly little trick with the car keys? I phoned Veena and she said she hadn't seen hide nor hair."

"I've just been… traveling."

"Oh, hark at her, Michael Palin. Are you staying for tea? Because I haven't got anything in. I've been trying to keep your granddad on that macrobiotic diet, but he sneaks off and gets pork pies at the petrol station. Don't deny it, I've seen the wrappers in the car. Oh, I don't miss a trick. Now then, what were you going to tell me? What don't I know?"

Donna thought for a moment. "Nothing." She said at last.

"Good. Right, then you can sit there and cut out those coupons. Every penny helps. This new mortgage doesn't pay for itself. Dad, kettle on."

"Yeah, kettle on." Wilf nodded.

* * *

Grey and Harris had led Martha far away from the main factory, right into the bowles of the complex.

"What's he doing down here?" She said.

"He asked to see you." Harris replied.

"What, has he found something?"

They didn't answer, just beckoned her through a door. Martha stepped through but saw no sign of the Colonel. Instead, there was a lab littered with equipment that was clearly alien in origin. Alarmed, she turned to leave, but Grey and Harris grabbed an arm each and hit a button to close the door so no one could hear her screams for help.


	3. The School Of Geniuses

**Chapter 3: The School Of Geniuses:**

Private Ross Jackson had never known his dad. He'd been less than a year old when a UNIT representative had come to his mother's door to inform her that her husband was killed in action. Though they couldn't tell her the exact details, they'd assured her he'd died bravely (which Ross later discovered meant that he'd been crushed by a giant robot foot.) She'd spoken so strongly of him that Ross had determined to follow in his footsteps and make him proud.

The existence of aliens hadn't come as much of a shock to him. In fact, it explained a lot of things. A year into his service with UNIT and they seemed as common place as any other threat a soldier might have to deal with. Even the Doctor, who was regarded as a legend by all the ranks, seemed like an ordinary, reasonable chap once he'd chatted to him for a while.

"UNIT's been watching the Rattigan academy for a while. It's all a bit Hitler youth. Exercise at dawn and classes and special diets." He explained to the Doctor.

"_Turn left._" Said the satnav lady. The Doctor had decided to call her Lucy.

"Ross, one question." Said the Doctor. "If UNIT thinks ATMOS is dodgy…"

"How come we've got it in our jeeps?" He finished. "Yeah, tell me about it. They're fitted as standard in all government vehicles. We can't get rid of it 'till we prove something's wrong."

"_Turn right._" Said Lucy.

"Drives me round the bend." Said Ross, as he turned the wheel.

"Ah, that's good." The Doctor grinned.

"Timed that perfectly."

"_This is your final destination._"

They pulled up outside the front of the academy's main building. The grounds were littered with streams of students running round in tracksuits. One figure was stood still, overlooking everything. This, they presumed, was Luke Rattigan himself.

"Is it PE?" Said the Doctor. "I wouldn't mind a kick around myself. I've got me daps on."

"You must be the Doctor." Said Luke. "Your commanding officer phoned ahead."

"Ah, but I haven't got a commanding officer. Oh, this is Ross. Say hello Ross."

"Good afternoon sir." Said Ross, but Luke gave him the barest of nods.

"Now shall we take a look?" The Doctor grinned. "I can smell genius. In a good way of course."

* * *

The main science lab could have been lifted from the pages of a sci fi comic. Littered with devices most human beings couldn't even have identified, if shown. Those schoolchildren led the world in certain areas of research.

Most visitors at this point would adopt a neutral expression and nod along as they were shown around. The Doctor however, squeed in delight and rushed forward like a child let loose in a sweetshop. "Oh, now, that's clever! Look. Single molecule fabric, how thin is that? You could pack a tent in a thimble. Ooo! Gravity simulators! Terraforming, biospheres, nano-tech steel construction! This is brilliant. Do you know, with equipment like this you could, oh, I don't know, move to another planet or something?"

"If only that was possible." Luke smiled.

"If only that _were_ possible." Said the Doctor. "Conditional clause."

Luke's eyebrows narrowed briefly. "I think you'd better come with me." He led them through to his living room. "You're smarter than the average UNIT grunts. I'll give you that."

"He called you a grunt." The Doctor said to Ross. "Don't call Ross a grunt. He's nice. We like Ross. Look at this place!"

Luke's quarters were certainly large and luxurious. Full of artistic decorations, entertainment equipment and elaborately shaped comfy furniture. It was lavish but it didn't look particularly lived in. Clearly he didn't often have people round.

"What do you want?" Rattigan snapped.

"I was just thinking. What a responsible eighteen year old! Inventing zero carbon cars? Saving the world."

"Takes a man with vision." He smiled.

"Mmm, blinkered vision. Because ATMOS means more people driving. More cars, more petrol. End result, the oil's going to run out faster than ever. The ATMOS system could make things worse."

"Ah, that's a tautology!" Luke snapped. "'cos you can't say ATMOS system. Because it stands for ATMospheric Omissions System. So what you're saying is ATMospheric Omissions System system. Do you see now, Mr conditional clause?"

The Doctor peered at him. It wasn't often that people outsmarted him. He wondered if Luke felt the same way about talking to him. "It's a long time since someone said no to you, isn't it?"

"I'm still right though." He said smugly.

"Not easy, is it, being clever. You look at the world and you connect things, random things, and think, why can't anyone else see it? The rest of the world is so slow."

"Yeah." Luke said neutrally, not sure what to make of this man.

"And you're all on your own."

"I know." Luke hoped this man would change the topic soon.

"But not with this." The Doctor moved on, waving the ATMOS device over his head. "Because there's no way you invented this thing single handed. I mean, it might be Earth technology, but that's like finding a mobile phone in the Middle Ages. No, no, I'll tell you what it's like. It's like finding this in the middle of someone's front room. Albeit it's a very big front room." He gestured to a metallic box, the size of a small shed, with one open end and a cylindrical chamber, with glowing blue lights, on the inside. There was a control panel at the end.

"Why, what is it?"

"Yeah, just looks like a thing, doesn't it? People don't question things. They just say, oh, it's a thing." He stepped in and had a look at the control panel.

"Don't touch it!" Luke said quickly.

"But me, I make these connections. And this, to me, looks like a teleport pod." He hit a likely looking button and the academy promptly vanished around him, to be replaced by the deck of a spaceship. A spaceship crewed by Sontarans.

Within seconds, they'd all turned to stare at him. "We have an intruder!" Shouted one of them.

"How did he get in then?" The Doctor grinned. "In tru da window? Goodbye?"

He hit the controls again and zapped himself back to Luke's living room. Where he and Ross were looking startled for entirely different reasons. The Doctor rand over to stand behind them. "Ross, get out! Luke, you've got to come with me." But Luke didn't seem intent upon leaving.

Hearing the teleport whirring again, the Doctor flashed his sonic at it before more than one figure had got through. The lights went out in the machine.

Undaunted, the creature stepped forward and raised its gun.

"Sontaran!" The Doctor shouted. The figure paused. "That's your name, isn't it? You're a Sontaran. How did I know that, hey? Fascinating isn't it? Isn't that worth keeping me alive?"

Ross brought up his sidearm. "I order you to lay down your arms, in the name of the Unified Intelligence Taskforce!"

"That won't work." Said the Doctor, as he idly scanned the room around him. "Cordolaine signal, am I right? Copper excitation stopping the bullets."

"How do you know so much?" Demanded the Sontaran.

"Well…"

"Who is he?"

"He never gave his name." Said Luke.

The Doctor, meanwhile, had gone to fiddle with a table football table that looked like it hadn't been fiddled with before. "But this isn't typical Sontaran behaviour, is it? Hiding? Using teenagers, stopping bullets? A Sontaran should face bullets with dignity. Shame on you!"

"You dishonour me sir!"

"Yeah? Then show yourself."

"I shall look my enemies in the face!" Staal reached up and pulled his helmet off. Underneath, was a round, hairless head, with brown leathery skin. There were ears, sunken into the sides.

"And your name?" Said the Doctor.

"General Staal of the Tenth Sontaran Fleet. Known as Staal the Undefeated!"

Oh, that's not a very good nickname. What if you do get defeated? Staal the-Not-Quite-So-Undefeated-Anymore-But-Never-Mind?

"He's like a potato. A talking baked potato." Ross gasped.

The Doctor was looking over a hand shaped sculpture on the table. "Now Ross, don't be rude. You look like a pink weasel to him." He dropped the sculpture and picked up a bat and ball, bouncing one with the other. "The Sontarans are the finest warriors in the galaxy. Dedicated to a life of warfare. A clone race, grown in batches of millions. With one tiny weakness."

"Sontarans have no weakness!" Staal shouted.

"No, it's a good weakness."

"What are you, an idiot?" Luke cried. "Only an idiot would provoke him."

"No, but. They're fed by a probic vent on the back of their necks. That's their weak spot. Which means they must always face their enemies in battle. They can never turn their backs, isn't that brilliant?"

"We stare into the face of death!" Shouted Staal.

"Yeah? Well. Face this!" He bounced the ball high and wacked it at the back of the teleport. It bounced off and smacked the Sontaran right in the phobic vent, it collapsed to the ground.

"What did you do? What's he done?" Luke shouted, running forward to help the stricken Sontaran.

"Run!" The Doctor led Ross out the door, through the hall and into the waiting jeep.

"Don't touch me!" Staal shook Luke off. "A Sontaran would rather be court martialled than show pain." He got to his feet. "I must return."

"But he broke the teleport." Said Luke.

"Ha! Primitive sonic trickery!" Staal zapped the machine with his wand and the lights came back on. He and Luke stepped in and he ported them up to the ship. "Our presence is known. Soldiers, we move to a war footing."

"I see you face battle open skinned." Said a Commander. "Mind if I share this honour?"

Staal thought for a moment. "You may."

"Thank you sir." He pulled off his helmet, to reveal a head almost identical to his General's.

Luke looked back and forth between them and decided to ask a question that had been nagging at his mind since he'd first seen Sontarans without their helmets. "How do you tell each other apart?"

"We say the same of humans." Staal replied.

"Tell me boy." Said the other Sontaran. "How many cars have been ATMOS converted?"

"They've gone worldwide, but only half." Said Luke.

"Which means four million cars." Said Staal. "A fine arsenal."

"Is it enough to trigger the conversion?" Said the Commander.

"Oh yeah, the tests works brilliantly!" Luke laughed. "I mean, 52 deaths in the same second. That is so cool!"

"Is the temperature significant?" Said Staal.

"Er, no." Luke said awkwardly. "It's just an expression. But I'll get my people ready general. Just tell me when."

"Have we infiltrated UNIT?" Said Staal.

"The process had begun sir." Said the Commander.

"Then you'll see it completed, Commander."

"Yes sir." The Commander headed for the teleport. He hit some buttons and was instantly transported to the lab beneath the ATMOS factory, where Martha Jones was strapped to a table, with a helmet covered in wires on her head.

"Will someone tell me what's going on?" She demanded, before catching sight of the new arrival. "O… k. Look, you're not the first aliens I've seen. Just tell me who you are."

"Commander Skorr of the Tenth Sontaran Fleet. Known as Skorr The Blood Bringer."

Martha hadn't thought he was friendly. But a name like that removed any doubt. "And what have you done to those soldiers?"

"Simple hypnotic control, like the factory drones. But with you, we require something a little more complex." He went to the vat of green liquid and hit some buttons. The liquid bubbled and rippled. A human arm rose from beneath the surface, flexed the fingers briefly and then returned to the depths.

"What is that?" Gasped Martha.

"In a short while." Said Skorr. "That will be you."

* * *

Hanging 100,000 Km above the Earth, the Sontaran battle station made a truly frightening sight. Their militaristic culture cared little for aesthetics. Instead, they kept everything spikey and jagged, with weapons sticking out here and there. All this to let enemies know this ship was not to be messed with. It also had about a hundred smaller battle spheres on board, ready to be launched to engage anything that came their way.

On its bridge, Luke was looking at the Earth. Like anyone who'd ever seen it, he was amazed by how small an insignificant the continents looked from up here. If more people could have seen this, they might gain a sense of perspective. It would stop them making so many poor choices. People slaughtering each other in their masses when they should cooperate. Destroying the world's resources for their own selfish gains. Or worse, rewarding people for being stupid. People brought up on a diet of reality TV and celebrity culture and an educational system set up to tell everyone they were brilliant, to the point that they almost seemed to pity anyone who bothered to read and gather knowledge. The moment anyone had offered him a way out, he'd jumped in with both feet. Even if it meant the death of everyone on the planet. They weren't worth saving.

"War could never come too soon." Said Staal. "Take a last look boy."

"It was never big enough for me." Said Luke.

"I like your ambition." Said Staal.

"This Doctor. He had a UNIT jeep. It should have ATMOS installed."

Luke could guess the expression on Staal's face was somewhere between alarm and rage. "You said he never gave his name!"

"He… didn't. He just said Doctor. Does that mean something?"

Staal hissed. "There is an enemy of the Sontarans known as the Doctor. A face-changer."

"You mean he's alien too?" Luke said, amazed.

"Legend says that he led the battle in the last great Time War. The finest war in history and we weren't allowed to be a part of it. Oh, but this is excellent. The last of the Time Lords will die at the hands of the Sontaran Empire, in the ruins of his precious Earth!"

* * *

Martha was tugging furiously at the straps round her wrists, but they were secured tight.

"It is inadvisable to struggle." Said Skorr. "The female has a weak thorax."

"But what are you doing?" She demanded.

"Completing mental transfer. The clone needs full memory access."

"C-clone?"

The fluid stopped bubbling at this point and a human figure began to rise up. Martha thought it looked familiar, but then it turned to face her and she gasped. It had her fact it looked identical to her in almost every way.

"No, you can't." She gasped.

"You will sleep, girl. Sleep, and keep the memories alive. Memories we can use in battle." He pressed a button and Martha felt an overwhelming tiredness wash over her. Though she fought to stay awake, it made no difference and she was soon under.

In the tank, her clone swam over to the edge and pulled an umbilical cord out of her back.

* * *

"We have the Doctor's vehicle." Said a technician.

"An ordinary death for such a remarkable enemy, but proceed." Said Staal.

* * *

"Greyhound 40, to trap 1." The Doctor said into the radio. He'd been trying to make contact ever since they'd left but he got nothing but static.

"Why's it not working?" Said Ross.

"It must be the Sontarans. If they can trace that, they can isolate the ATMOS."

"_Turn Left._" Said Lucy.

"Try going right." Said the Doctor.

"She said left."

"I know. So go right."

Ross spun the wheel right but the car veered to the left and onto waste ground. None of the controls responded. Even the doors were locked.

The Doctor tried sonicing the satnav. "It's deadlocked. I can't stop it!"

"Let me." Ross whacked it with the butt of his rifle.

"The satnav's just a box. ATMOS goes through the whole car." Said the Doctor.

They looked out the windscreen at the river that was fast approaching.

* * *

"Are they going in the water?" Luke giggled. "I love it, with the water!"


	4. Carmageddon

**Chapter 4: Carmageddon:**

Ross hammered hard on the windows. But they were designed to be shockproof, and would take a lot more force to shatter. He didn't dare try and shoot them with the car bouncing around the way it was, as it sped across the waste ground towards the river.

The Doctor leaned into the satnav box. "You're programed to disobey my instructions, right? Everything I say, you'll do the opposite?"

"_Confirm._" Said Lucy.

"Then drive us into the river! Go on! I order you to drive us into the river!"

The box whirred for a few seconds, as the river came ever closer. "_Confirm._" It said and the brakes came on, bringing the jeep to a halt right on the riverbank.

Finding the doors unlocked, the Doctor and Ross wasted no time in bailing out and running for cover. Not least because Lucy was confused by these new set of orders, flashing up error messages and running the cooling fans at maximum.

"Turn left. Right. Turn left right leftrightleftright…" Finally, the box overheated, going up in a tiny plume of smoke and a couple of sparks.

"Is that it?" Said the Doctor, disappointed.

* * *

The malfunctioning satnav had caused the dot on the Sontarans' screen to appear in the middle of the river. They watched as it winked out.

"Mission accomplished sir. The Doctor is dead."

"Excellent. Then we shall proceed." Said Staal. He hit a button on his intercom. "Is the operative in place?"

* * *

Martha's clone had pulled on her human self's uniform and engagement ring, as well as rinsing the embiotic fluid off and styling her hair.

"Do you understand your purpose?" Said Skorr.

She nodded. "Ready to advance the great Sontaran cause sir."

"Then get to work."

"Ok. You two, with me." She led the Grey and Harris out and back up the stairs.

* * *

Fortunately, they'd abandoned the jeep not far from the Nobles' house. The Doctor knocked hard on the door, before Donna arrived. "You would not believe the day I'm having."

* * *

The Doctor got down on the ground to have a look at the ATMOS box on the exhaust of Sylvia Noble's car. He then opened up the bonnet to have a look at the components within the engine itself. Donna, meanwhile, was dialling her phone.

"Should I requisition us a vehicle sir?" Said Ross.

The Doctor nodded. "Anything without ATMOS. And don't point your gun at people."

Ross went off to find one. He'd had no intention of taking it at gunpoint anyway.

"Is it him?" Said Wilf's voice. "Is it the Doctor?" He rushed over and came to a halt. "It's you!"

"What?" The Doctor glanced over and abruptly did a double take as he saw the man he'd last seen manning a newspaper stall on Christmas Eve, when the rest of London had evacuated the city. "It's you!"

"What, you've met before?" Said Donna.

"Yeah, Christmas Eve. He vanished right in front of me." Said Wilf

"And you never said?"

"Well you never said!" He turned back to the Doctor. "Wilf, sir, Wilfred Mott. You must be one of them aliens?"

"Well, yeah, but don't shout it out." The Doctor grinned, and shook his hand. "Nice to meet you properly Wilf."

"Wow, an alien hand."

"Is anyone answering?" The Doctor asked Donna.

"It's just ringing. What is it son-ta-rons?"

"Son-tar-ons. They're behind ATMOS. But remote controlling cars isn't enough. There must be something more to it." If they planned to invade, disrupting the enemy's transport networks would certainly help. But a race with spaceships already had a stronger transport system anyway.

Finally, Martha's voice came on the phone. "Don't tell me. Donna Noble."

The Doctor took it off her. "Martha, it's the Sontarans. They're in the factory. Tell Colonel Mace code red Sontaran. They should be in the files. But if they meet them, tell them not to start shooting. UNIT will get massacred. You got all that?"

* * *

"Code red Sontaran." Martha nodded. "Gotcha." And she rang off.

"Doctor Jones?" Mace found her at this point. "Found anything?"

"Nothing to report." She said.

Mace nodded and left.

* * *

"You tried sonicing it before." Said Donna, as the Doctor tried again.

"Yes' but now that I know it's Sontaran, I know what I'm looking for."

"The thing is, Doctor," said Wilf, "Donna's my only grandchild. I want you to promise me you'll take care of her."

"She takes care of me."

"Ah, that's my girl. She was always bossing people about. Even when she was a baby. Our little general, we used to call her. And then she got older and she was bringing the boys back. A different one every week."

"Don't start." Donna sighed.

"'ere, who was that posh one, with the nail varnish."

"His name was Chris. He lives in Kilburn now… with a man."

"Ah!" The Doctor cried suddenly. "It's a temporal pocket!" A brief flash passed over the box and a collection of little nozzles appeared. "Just a second out of sync with real time. I knew there was something else hidden inside."

"I don't know, men and their cars. Sometimes I wish I were a car." Sylvia approached, but she too halted when she saw the Doctor. "Oh, it's you! Doctor… whatever you said your name was."

"Yep, that's me." Said the Doctor, without looking up from his sonicing.

"What, have you met him too?" Said Wilf.

"Dad, it's the man from the wedding! When you were laid up with Spanish flu. I'm warning you. Last time that man turned up, it was a disaster."

As if ATMOS had a sense of irony, the nozzles all spat out a cloud of white smoke, sending them scurrying away.

* * *

"A converter had been activated." Said a technician.

"What?" Cried Staal. "Show me where!"

The technician brought up a map.

"London." Said Luke. "That's Chiswick."

"Who can have such knowledge?" Said the tech.

"Only the Doctor!" Cried Staal. "So he survives! Very well. He will choke to death along with the humans. Soldiers, we move to the final phase. We move to war. Prepare for the subjugation of earth!"

Seconds later, a stream of dozens of fully armed Sontaran infantry came marching out and towards the teleport in neat formation.

"Trigger the converters!" Shouted Staal. "And deadlock every single one!"

* * *

The Doctor, meanwhile, deactivated the ATMOS device and waved away the cloud of smoke that surrounded the engine. "There, that should stop it."

"What did I tell you!" Shouted Sylvia. "He's blown up the car! What sort of Doctor blows up cars?"

"Oh, not now mum." Donna sighed.

"I should have made an appointment!" Her mother stormed away.

The Doctor, meanwhile was sniffing the air. "That wasn't just exhaust fumes, there was something toxic in that gas."

"What so like poison gas? But if they've got toxic gas on every car on Earth…" Donna looked up and down the street, where two or three cars were parked outside every house, each with a sticker in the window, announcing that they had ATMOS installed.

"It's not safe. I'll get it off the street." Said Wilf, climbing into the car.

"No!" Shouted the Doctor, but too late. At that exact moment, the Sontarans' activation signal came through. The doors locked and the engine roared into life.

"Granddad get out of there!" Shouted Donna. "Turn it off!"

"I can't, I didn't turn it on!" Shouted Wilf, holding up the keys.

The Doctor tried to deactivate the converter again, but it wouldn't work this time. Nor would the door locks.

* * *

It wasn't just on Donna's street. A cloud of thick white smoke poured out of half the cars in the world. Anyone stood nearby was quickly engulfed in the chocking gas, which rapidly radiated outwards, filling whole streets and whole car parks.

In the ATMOS factory, Colonel Mace hurried down to the main entrance hall, where the handful of jeeps they'd parked inside were also pouring out gas. "Turn them off!" He shouted. "Turn all of them off!"

"We can't sir. Something's controlling them!" Shouted a Corporal. "It's every car on the planet!"

"Well find a way!"

Several soldiers at this point, tried to shut down the engines by shooting at them, something that was difficult to do since military vehicles are designed to withstand a certain amount of bullet damage. Others just scrambled for cover.

Only one figure remained calm. Martha strolled through the area, looking around with a sense of satisfaction. The plan was underway successfully. Time for her to get to work.

* * *

The Doctor physically ripped some cables from the ATMOS box and went to see if that had helped. But the doors were still locked.

"There's gas in the car!" Donna screamed, while her mother watched in horror from the doorway. "He'd gonna choke!"

The Doctor returned to the engine and tried even more furiously to find something that wasn't deadlocked. It was only now that he got a good look down the street at the lines of cars that were producing the gas, and the rapidly thickening smog.

* * *

"Four million weapons." Staal said triumphantly. "Sontar ha. Sontar ha!" He punched his palm with his fist as he chanted. "Sontar ha! Sontar ha!"

Luke watched as every Sontaran on the bridge joined in with his routine. "Sontar ha! Sontar ha! Sontar ha!" Correctly guessing this was some sort of war dance, he joined in. "Sontar ha! Sontar ha! Sontar ha! Sontar ha! Sontar ha!" They chanted triumphantly as the humans chocked below.


	5. Comunication

**Chapter 5: Communication**

The Doctor tried undoing the bolts on the door panels, but was finding them incredibly difficult to shift, even with the sonic, meanwhile Donna was screaming for him to hurry up.

Suddenly, Sylvia stepped up, dropped the bonnet lid and raised the axe she was carrying high. Before smashing it through the windscreen. The others just looked on stunned. "Well don't just stand there, help me get him out!"

* * *

In the ATMOS factory, soldiers were working in groups to shove the stationary cars as far away from the building as possible. They'd managed to disable a few of them with well-placed explosives or several reams of ammunition, but they'd been forced to abandon this method when it became apparent that smog was drifting in from the town anyway. Plus, they'd need the ammunition if they actually encountered aliens today.

"Get everyone into the factory!" Shouted Mace. "Secure the ground floors and seal the entrances." He made his way to headquarters, where the banks of operatives were struggling to deal with the sudden onrush of information. Not to mention the phones that were ringing. It tended to happen whenever the aliens invaded. "What have we got?" He said to his senior Captain.

"ATMOS has gone berserk, worldwide." She replied, and brought up a live map, showing red zones, concentrated around where the major cities were and spreading slowly outwards.

As most of UNIT stared at their own screens, no-one paid Martha Jones much heed. No-one needed to, they all knew her anyway. She patted one of them on the shoulder and gestured that she needed to use his machine, he stood up without another word. She keyed in her security code and logged into the NATO defence grid.

* * *

Donna and her mother supported Wilf to the door between them. "I can't believe you have an axe at the ready."

"Burglars." Sylvia shrugged.

"Get him inside." Said the Doctor. And seal up all the doors and windows."

"Doctor." Ross called from the window of a hackney carriage. "This was all I could find that didn't have ATMOS."

"Right. Donna, you coming?"

"Yeah." She said without hesitating.

"Donna!" Her mother was aghast. "Look what happens every time that Doctor turns up. Stay here, please!"

"You go my girl." Wilf said over her.

"Dad!"

"You go with the Doctor and do some good! That's my girl." He grinned as Donna climbed into the rear of the taxi.

* * *

After a few minutes, Martha had uploaded the necessary programme to her phone. She then went outside and pressed some buttons on the communicator the Sontarans had given her.

"The operative had completed her task accordingly." Said Skorr.

"Not bad for a female." Said Staal. "Now she must be protected."

"I'll prepare an attack squadron."

To one side Luke was twitching with excitement. "This is it, isn't it? This is war!"

"How does it feel boy?" Said Staal.

"Magnificent!" Luke grinned.

* * *

The Doctor's return to the factory had been slowed somewhat by the roads jammed with people climbing out of their cars, through smashed windows, and running for the nearest buildings. Fortunately, the Sontarans' plan relied on the cars remaining intact, so most had come to a halt where they stood instead of crashing, but the blocked roads had forced the Private to go a long way out of his way to avoid the jams.

Finally, they pulled up at the factory barrier and the Doctor hopped out. "Look after yourself Ross. Get inside the factory and keep your head down."

"Will do." Ross nodded. He picked up the radio. "Greyhound 40 to Trap 1. I've returned the Doctor safely."

* * *

"Roger that." Said the Colonel.

Martha, who'd been listening in, burst into the room at this point. "Sir. Message from the Doctor. He says code red Sontaran."

"All units, code red Sontaran." Mace said into the radio.

Martha relaxed. Her cover was still secure.

* * *

Donna coughed and spluttered the moment she stepped out of the relatively fresh air of the car. "This air is disgusting."

"Not so bad for me. Go on, get in the TARDIS. Ooh! I've just realised, I haven't given you a key yet!" He pulled a key from his pocket. "That's yours. Keep it safe. Quite a big moment really."

But Donna was too busy coughing to get as emotional as Rose or Martha had. "Maybe we can get sentimental when the world's finished chocking to death!"

"Good plan." He handed it over and ran in the direction that led away from the TARDIS.

"Where are you going?" Called Donna.

"To stop the war!" He shouted back. He'd left UNIT forces to blunder into battle and get cut down too often in the past. This time, he was going to take precautions to make sure they stayed out of the way.

Donna hurried up to the TARDIS and pulled the doors open, gasping at the smog free air on the far side.

* * *

The Doctor burst into the control room. "Right, here I am. Whatever you do, Colonel Mace, do _not_ engage the Sontarans in combat. There's nothing they like better than a war, so don't give them one. Just leave this to me."

"And what are you going to do?" Said Mace.

"I've got the TARDIS. I'm going to get on board their ship."

Martha listened as he talked and pulled out her phone to key in instructions for Grey and Harris. Less than a minute later, the Doctor tapped her and said "Come on."

Amidst all the smoke and confusion, no one noticed the two soldiers step away from the main group. They went over to an alley between two buildings and found the TARDIS stood there. Harris attached a couple of targeters to the sides of the box and picked up his radio. "Ready for transport." As they walked away, a blue haze passed over the TARDIS and it was instantly transported to the Sontaran control room.

"Behold!" Staal declared. "The weapon of a timelord, in Sontaran hands."

Luke had been watching their operations with some fascination up to this point, but decided it was time to get on. "It's time I made a move sir. I've got soldiers of my own. I'll tell them of the honour and the glory sir. I'll tell them planet fall is coming!" He made his way to the teleport and ported down.

"He has behaved exactly as predicted." Said Skorr.

"None of the humans can guess our true purpose." Said Staal.

Donna had felt a minor jolt as the Sontarans had grabbed the ship. She pulled the door open a crack to see what had happened. Outside, she saw a room full of Sontarans and hurriedly shut it again. She didn't know how she'd got there. Btu she did know she had to keep quiet.

* * *

The Doctor ran and stood in the spot where the TARDIS had been and looked all around forlornly.

"But where's it gone?" Said Martha. "It was right here."

The Doctor flicked his tongue a few times. "Taste that in the air. A sort of metal tang. Residual teleport. They've taken it. The Sontarans have taken it. Now I'm stuck down here, like an ordinary person, like a human. How rubbish is that! I mean, no offense, but come on!"

"So what do we do?" Said Martha.

"Well… It's shielded, they should never have been able to detect it…" He paused to peer at her.

This got Martha worried. If anyone here could spot a Martha imposter, it was the Doctor. "What?" She said, in mock confusion.

"I was just wondering if you'd phoned your family."

"No. Why?"

"The gas. Warn them to stay inside."

"Of course I will." Said Martha, trying to look as though she'd only just thought of it. It helped that she had just thought of it. She had her human self's emotions, and that made part of her wonder if her family were alright. She reminded herself that they weren't realy her family and quickly changed the subject. "But what about Donna? Where's she?"

"Oh she's… Gone home. Visiting her family. She's not like you. She's not a soldier. "Right then… Avante!"

* * *

The school stood at the top of a hill, which gave them a view over half of London on a clear day. Today, the students were standing on the lip of the hill, watching in silent horror as the gas cloud over London thickened and spread outwards. They could see the tops of the taller buildings poking through but the streets were an opaque haze.

"Turn away." Luke got their attention. "Civilisation is falling."

"It's all in the News sir." Said the head boy, Steve was his name.

Luke just grinned back. "It's time for you to find out what all your work was for!"

* * *

"Right! Change of plan." Said the Doctor, as he hurried into the UNIT control centre.

"Good to have you fighting alongside us, Doctor." Said the Colonel.

"No. No fighting from me. As in not-fighting, not hyphen fighting. You got that? Now, does anyone know what this gas is yet?"

"We're working on it." Said Martha, who'd taken a sample and was running any test which would tell the humans nothing.

"It's harmful." Said a Captain. "But not lethal until it reaches 80% density. We're getting the first fatalities from the centre of Tokyo."

"And you are?" Said the Doctor.

"Captain Marion Price sir." She saluted, the Doctor rolled his eyes once more.

Mace brought up a RADAR display. "Jodrell Bank's traced the signal, coming from 5000 miles above the Earth. We're guessing that's what triggered the cars."

"The Sontaran ship." The Doctor nodded.

"NATO's gone to defcon 're preparing a strike."

"You can't do that. Nuclear missiles won't even scratch the surface. Let me talk to the Sontarans."

"You don't have the authority to speak on behalf of the humans."

The Doctor went along the control panels adjusting dials. "I've got the authority. I had the authority long ago." He soniced the main server and the Sontaran bridge came up on the main screen. "Calling the Sontaran command ship. Under Jurisdiction Two of the Intergalactic Rules of Engagement."

* * *

Donna heard his voice and hurried over to the TARDIS scanner. It briefly displayed an image of a blonde girl, who seemed to be shouting the Doctor's name. A second later, she faded to reveal a view of the Doctor in UNIT HQ. The girl could be dealt with later.

"Doctor, it's me!" Donna shouted, but got no response. Clearly, he couldn't hear her.

* * *

"Ah, Doctor. Breathing your last?" Said Staal.

"They're like trolls." Gasped Mace.

"Yeah, isn't that diplomacy?" Muttered the Doctor. "Tell me Staal. Since when did the Sontarans become cowards?"

"How DARE you?" Roared Staal.

Mace rolled his eyes. "Oh, so THAT's diplomacy?"

"You impugn my honour!" Shouted Staal.

"I'm realy glad you didn't say belittle. 'cos then I'd have had a field day." He sat back and put his feet up on a console." Aggravating your enemies was a good way to stop them thinking straight. Especially about what they were saying. "But poison gas? That's the weapon of a coward and you know it… Or, is there something else? What are you lot up to?"

"A general would be unwise to reveal his plan to an opposing officer."

"Ah, the war's not going well then!"

"Such a suggestion is…" Staal began, but Mace interrupted.

"What war?"

"The war between the Sontarans and the Rutons." Said the Doctor. "It's been raging, far out in the stars, for fifty thousand years. Fifty thousand years of bloodshed, and for what?"

"For victory!" Staal declared "Sontar-ha! Sontar-ha! Sontar-"

"Give me a break." Muttered the Doctor. He soniced the screen and the image of the Sontarans was briefly replaced with a children's cartoon.

Mace decided to use this interval to voice his objections. "Doctor! I must insist that this dialogue is handled by proper Earth representation!"

The Doctor ignored him and brought the Sontarans back up. "Finished?"

Staal would have narrowed his eyebrows in he'd had any. "You may not be so quick to gloat when you've seen our prize. We are the first Sontarans in history to capture a TARDIS!" He walked over to stand next to it, knowing that the camera would follow him. "The spoils of war."

The Doctor didn't look overly concerned. "Well, as prizes go that's… noble. As they say in Latin. Donna nobis pacem."

* * *

Seized by sudden hope, Donna leaned into the screen. "That's me! I'm here!"

"Did you never wonder about its design? It's a phone box. It contains a phone. A telephonic device for communication. Sort of symbolic. Like, if only we could communicate, you and I."

"All you have communicated is your distress, Doctor." Said Staal.

But Donna could see who he was really talking to. She hurried over and pressed the same button the Doctor had earlier. Martha's phone popped out. "But who do I phone?"

"Big mistake showing it to me though." Said the Doctor. "'cos I've got a remote."

"Cease transmission!" Shouted Staal. "Move the box out of the war room. Out of range!"

* * *

In UNIT HQ, the Sontarans' image went blank.

"Well that achieved nothing." Said Mace.

"You'd be surprised." The Doctor smiled.

* * *

"What number are you on?" Donna shouted at the now blank screen. She had a look through the contacts. "You haven't even got a number! What do I do? Doctor!"

She felt another jolt as a team of Sontarans lifted the TARDIS onto a trolley and wheeled it deeper into the ship.


	6. Fools' Courage

**Chapter 6: Fools' Courage**

Luke had spent a long time rehearsing this speech in his mind, it was hard to hide his glee that the moment had finally arrived to make it. "All this stuff we've been building. All this invention. Where's it been heading? Gravity densifiers, hydroponics, atmospheric conversion, ecoshells. More than enough to build a brand new world."

"Look, I haven't got time for this." Steve interrupted. "I've got to phone my parents."

"Oh, but this isn't just theory." Luke grinned. "I'm talking Planetfall, for all of us. A brand new start for a brand new human race." He brought up a hologram of a star map. "Look. A new world, far out, beyond Alpha Geminorum, just waiting for us. Its official destination is Castor Thirty Six. I think of it as Earth Point Two. I did wonder about Rattigan's World, but we can take a vote on that."

"What are you talking about?"

"This is where we're going! I have partners willing to take us there."

"Oh he's lost it! I haven't got time for this." One of his best pupils, Rita was her name, made her way towards the door.

But she'd have to walk past him to get there, and he promptly blocked her path. "Where are you going?"

"To find my brother!"

"I didn't say you could leave!"

"I told him to put ATMOS in his car. I have to know if he's safe!"

"Stay where you are!" Luke whipped a gun from his belt and pointed it in her face. Hearing horrified gasps from everyone round the room, he realised that this revelation wasn't going as he'd rehearsed it. He'd expected hostility from some of them, it was only sensible. He hadn't planned what to do if all of them tried to stop him.

"What do you think you're doing?" Said Rita.

"Luke… put that down." Steve said uncertainly.

Luke waved the gun round all the people gathered round him. "But, I did this for you, don't you see? We've spent all our lives excluded. The clever ones. They've laughed at us and pulled us down, those ordinary people out there! Those cattle. This is our chance to leave them behind. I did this for you!"

"You want them to die?" Cried Steve.

"And I chose you to survive! With planet fall, we can do anything! We can build, and breed, and prosper…"

"We're going to breed?" Cried Rita, aghast at the prospect.

"I designed a mating programme." He grinned. "I planned the whole thing!"

If he expected the students to be impressed, he was sourly mistaken. "Well then…" Rita laughed. "Shoot me!" She walked round him and headed for the door. Having already decided she'd rather choke to death than go along with Luke's insane scheme, she already had nothing to lose than taking a chance at him shooting her. At worst, it would be a quicker death.

"Stay where you are!" Luke pointed the gun at her back. "I said stay where you are!" But he couldn't bring himself to shoot them. A fact the room full of geniuses was quick to pick up on, and they all got away from this madman as quickly as possible.

"Stay where you are, that's an order!" He shouted at them, but to no avail.

Steve was the last to go. "Rattigan's world? You are sick."

"I guess that just proves it!" Luke shouted after him. "I'm cleverer than you! I'm cleverer than anybody! You hear me?" He stomped his foot in anger. "I'm clever!"

* * *

Outside, the gas was thickening fast. Some people were trying to wreck their cars, but few had access to the necessary equipment, and with the roads blocked, there was very little way to bring it in.

Most either hid indoors, and fought a losing battle to keep the gas from getting in, or fled the cities altogether, trekking out across the countryside in hordes as though fleeing a Biblical plague. Others took to the sea, turning coastlines everywhere into Dunkirk. But the gas was spreading outwards, moving almost as fast as they could.

Wilf watched as a chocking woman staggered down the street, searching for shelter. He tried calling to her but she disappeared into the smog, apparently unable to hear him over the engine noises.

Hearing the phone ring, Sylvia went to pick it up. "Donna! Where are ya sweetheart?"

Donna could have cried from hearing her mother's voice. She was busy staring at the main door and wondering how long it would take the Sontarans to break in, and how long she could hide in the corridors if they did.

"Is that her?" Said Wilf.

"Oh, just finish the job. Your granddad's sealing us in. He's sealing the windows. Our own house, and we're sealed in. All those things they said about pollution, they're really happening!"

"There's people working on it." Donna said uncertainly. "They're gonna fix it. I promise."

"Oh, like you'd know. You're so clever."

"Oh don't start. Please don't."

"Oh that's not gonna help Sylvia." Said Wilf. "Give it here. Donna, where are you?"

"It's… sort of hard to say."

Is he with you? Is the Doctor there?"

"Oh, the Doctor." Sylvia muttered scathingly.

"No." Said Donna. "I'm on my own."

"But he said he'd keep you safe!"

"He will gramps. There's something he needs me to do."

"Well, I mean, the whole place is covered. The whole of London, they're saying. The whole, the whole world. It's the scale of it, Donna. How can one man stop all that?"

"Trust me. If anyone can, it's him."

"Well... You tell him from me. If he doesn't, he'll have me to answer to."

"I will gramps. I've got to go now." Donna felt a single tear roll down her cheek.

* * *

Martha peered at the sample of gas in the container, then back at the readings she'd already looked over three times. She already knew what the gas was but she had to look busy. It was a skill she'd picked up during some of the quieter days at her old hospital. If she had nothing to do but didn't want to look lazy, she'd grab a stretcher and push it on a circular route that took it back where she'd started. But then that hadn't been her…

She was distracted from her train of thought when the Doctor snatched the clipboard from her hands. "There's carbon monoxide," she said quickly, "hydrocarbons, nitrogen oxides, but ten percent unidentified. Some sort of artificial heavy element we can't trace. You ever seen anything like it?"

"It must be something the Sontarans invented. This isn't just poison. They need this gas for something else. What could that be?"

Martha shrugged.

"Launch grid online and active." Announced Mace. "Positions."

"What?" Shouted the Doctor. "I told you not to launch!"

"The gas is at sixty percent density. Eighty percent and people start dying, Doctor. We've got no choice."

"Launching in 60, 59, 58, 57, 56. Worldwide nuclear grid coordinating. 54, 53…"

* * *

Staal looked at the readouts on the screen and laughed. "The planet is going nuclear! I admire them. The bravery of idiots is bravery nonetheless."

"The operative is in place sir." Said an aide.

"Commander Skorr, is the attack squadron ready?"

"Ready and eager for battle." Skorr's voice responded over the communicator. "We've been watching from down here. It'll be good to taste blood."

"Then proceed."

* * *

"Nuclear missiles won't dent that ship!" The Doctor shouted again.

"We have to try." Said the Colonel.

"North America, online." Said Price.

"The Shadow Proclamation will take this as a declaration of war!" Said the Doctor.

"United Kingdom, online."

"Does this proclamation say anything about the use of poison gas on a civilian population?"

"France, online. India, online."

"Right now it's just one renegade ship. If you do this, you'll bring the whole might of the empire down on you!"

"Pakistan, online. China, online. North Korea, online."

"We'll cross that bridge when we come to it."

"All systems locked and coordinated."

"You're making a big mistake Colonel. For once, I hope the Sontarans are ahead of you!"

"Launching in ten, nine, eight,"

"Your objection is noted."

"seven, six, five, four, three, two…"

As the Doctor just watched madness unfold with his hands in his hair, Martha pulled out her phone and looked at a display which read _Launch? Yes/No_. She tapped _No_. The screens promptly went blank.

"What happened?" Said the Colonel. "Did we launch?"

"Negative sir." Said Price. "The codes have been wiped. It must be the Sontarans."

"Can you override it?"

"I'm trying it now sir."

The Doctor looked more intrigued than concerned. "The Sontarand can withstand those missiles, so why are they so keen to stop you?" He turned to Martha. "Any ideas?"

"How should I know?" Said Martha, wishing her UNIT training could have taught her a bit more about undercover work. Still, it seemed to fool the Doctor.

* * *

"Now protect the operative." Staal's voice came over the communicator.

Skorr led his squadron of the Sontarans' most elite fighters out of the basement lab and towards the stairs in double file. Once there, they broke off and moved towards their assigned positions, having studied the layout and the UNIT troops' heat signatures carefully beforehand.

* * *

Ross took a look out the window and returned to the four men who were slumped against the wall. "It's stinking out there." He said.

"Much better in here." They nodded.

Hearing footsteps down the corridor, Ross shushed them. As the first Sontarans came into view he quickly said. "Hostiles in sight, at arms!"

The others got up to take positions across the corridor. Ross ducked into an alcove and got on the radio. "Code red. Sontarans in the factory grounds."

* * *

"All troops, code red, Sontarans sighted in factory. Prepare to engage." Said Mace.

"Get them out of there." Said the Doctor.

Mace thought for a moment. If they retreated, they'd only be stepping out into the poisonous fog. "All troops, open fire."

* * *

The soldiers next to Ross pulled the trigger, but the guns clicked in their hands.

"The guns aren't working." Said Ross. "Inform all troops, standard weapons do not work."

At this point the Sontarans fired. A laser struck each of his friends and they collapsed with a burning hole in their chest.

"Tell the Doctor it's that cordolaine signal. He's the only one that can stop it."

The Sontarans had advanced forward to get a line of sight. Scorr fired and Ross fell down.

* * *

"Greyhound… 40 report." Said the Colonel. "Greyhound 40, report."  
The Doctor's eyes narrowed. "His name wasn't Greyhound 40, his name was Ross. Now listen to me Colonel, and GET THEM OUT OF THERE!"

Mace sighed. "All units retreat. Evacuate the factory."

The men scrambled for the exits like mad, but found that the Sontarans had anticipated their moves and were moving forward to catch them at every junction. Some instinctively tried to shoot at them and naturally failed miserably.

Scorr saw one group of soldiers trying to make their way to the main entrance, spotting Sontarans in their way, one tried throwing a grenade but found that the signal stopped that going off too. He lazily shot the man down, while the others took out his friends, running in the opposite direction. "This is too easy. They're running like slimebait from a speelfox."

He led the others into the main warehouse, where those who had made it were running through a hail of Sontaran fire to get to the main doors. One UNIT man hit the door controls and they began to descend, leaving those who were left to hurry to get under them before the gap went.

Amidst all the chaos, Grey and Harris stepped away from the rest of the troops and up to the nearest Sontaran officer. "Reporting for duty sir."

The Sontaran shot both of them.

"This isn't war!" Scorr laughed. "This is sport!"

* * *

"They've taken the factory." Said Mace.

"But why?" Muttered the Doctor. "They don't need it. Why attack now? At times like this I could do with a Brigadier. No offense."

"No taken." Said Mace, who knew exactly what he was referring to. "Sir Allister's a fine man. Unfortunately, he's stranded in Peru."

"Launch grid back online." Said Price. But, seconds later, the screens went blank again, while Martha slid her phone back into her pocket. "The Sontarans are in the system. It's coming from within UNIT itself."

"Trace it." Said Mace. I want to know exactly where it's coming from. What's the situation with the gas?"

"66% in major population areas and rising." Said Price.

As the Doctor had a closer look at the gas distribution, Mace went over to his radio. Making sure the Doctor wasn't listening, he said… "Trap 1 to Hawk Major, what is your location? ... We require air support at the ATMOS factory, how quickly can you be here?"

* * *

"Commander Scorr reports victory, with many glorious deaths." Said a Sontaran operative, as Luke teleported up to the bridge. He'd given his students 15 minutes before realising they weren't going to change their minds.

"Sorry to report, sir, I've failed. They wouldn't come. The students, they didn't have the imagination to believe." Luke said.

"A pity." Said Staal. "We've lost our target practice."

"W-What do you mean?" Luke stammered.

"Upon arrival aboard this ship, your comrades would have been executed. Prehaps they were more clever than you thought."

Luke babbled for a moment, as several emotions fought for control of the vocal cords. "But you promised." Was all that came out.

"There was no Planetfall. Castor Thirty Six, indeed! We only needed you for installation of the ATMOS system."

"No, but I'm on your side! I did everything you wanted. A-And it's not ATMOS system. That's a tautology. It stands for ATMospheric Omissions System, so what you're saying is…"

"Execute him!" Shouted Staal. But Luke hit a button and teleported away before the order could be carried out.

"A cowards retreat." Said Staal. "Now close all teleport links with Earth. Isolate them as they perish!"

* * *

Down on Earth, Luke collapsed onto the floor of the teleport. He'd betrayed his planet, his people, even his friends to death over some empty promises. Now they'd all abandoned him. Even the Sontarans didn't want him. Unable to take it anymore, he broke down and cried.


	7. Revenge of UNIT

**Chapter 7:** **Revenge of UNIT**

In Mace's office, the Colonel was looking over the schematics of the factory with the Doctor. "Why are they defending the factory only after we arrived?"

The Doctor had been pondering that idea too, but suddenly realised. "Because they wanted UNIT here. You gave them something they needed. Something now hidden inside the factory."

"Then we'll have to recover it. This cordolaine signal, how does it work?"

"Oh, causes expansion of the copper coatings within the barrel. I think it might help if…"

"Copper casings… I'm on it." And he marched out the office and towards the main doors.

"For the billionth time, you can't fight Sontarans!" The Doctor shouted after him. When the Colonel failed to listen, he realised he'd have to move fast.

He went to the end of the row and tapped an operative. "Phone. I need your mobile." He whispered, careful to ensure no one else heard.

He took the phone back to the office and quietly shut the door behind him.

* * *

On board the TARDIS, Donna heard the phone ring and snatched it up within milliseconds. "What happened? Where are you?"

"Still on Earth." Said the Doctor. "But I've got my secret weapon."

"And what's that?"

"You."  
"Somehow, that's not making me feel better."

"I need your help to retrieve the TARDIS."

"Can't you just zap it down with that remote?"

"I haven't got a remote. I said that so they'd move the ship away from the war room. I'm sorry Donna, but I need you to go out and reopen all the teleport links. I can talk you through it."

"But there's Sont-a-rons out there."

"Son-tar-ans. But they're at battle stations now. They're not exactly milling about having coffee."

Donna gulped. She'd never really been a critical part of the Doctor's plans before. Certainly not on her own. "But what if they find me?"

"I know. I wouldn't ask you to do it normally, but I've got no choice. The whole planet is chocking Donna."

She took a breath. "What do I have to do?"

"The Sontarans have teleported in, which means they must have teleport technology inside the factory. But they've teleported it shut. I need you to unlock it."

But I can't even mend a fuse!"

"Donna! Stop talking about yourself like that. You can do this."

Donna crept up to the door and eased it open. The first thing she saw was the back of a Sontaran, stood on guard. She quickly shut the door. "There's a Sont-a-ron… Son-tar-an outside the door."

"They would have left a guard. Don't worry, there's a probic vent on the back of its neck. One blow knocks him out."

"But he'll kill me."

The Doctor rubbed his forehead. "I'm sorry. But you have to try."

Donna slowly made her way over to the console and took hold of the rubber mallet the Doctor had used earlier. She then took a breath and eased the door open further than before so she could tiptoe through.

Not daring to breathe, she crept up behind the guard, raised the mallet and swung it round, into the vent. The guard shuddered and then fell down.

"Back of the neck!" She whispered into the phone, gaining an impressed whistle from the Doctor.

"Now you need to find the teleport controls. They should have a label through them, like a T with a line through it, of two Fs back to back."

Donna looked around the bare storeroom. There was a single door at the end. "There's a door here. But there's no handles."

"There should be a switch by the side."

"There's a hand reader. But it's Sont-a-ron shaped. You need three fingers."

"You've got three fingers."

"Oh yeah!" She held her hand in a Vulcan salute and pressed it down. The door slid open. "I'm through."

"Oh you are brilliant."

"Shut up." She said. "Right. T with a line through it."

"I've got to go. Keep the line open."

As he went silent, Donna heard the ominous clank of marching boots. At a loss, she ducked behind a support column and curled up on the floor. She watched as a series of Sontaran trooped past, praying that none of them would look her way.

* * *

The Doctor had seen the Colonel returning to the HQ announcing battle stations.

"I said you don't stand a chance!" The Doctor shouted.

"We need everyone in position." Said the Colonel. "And that means you too Doctor." Said Mace, tossing him a gas mask.

The Doctor sighed and went to follow. At least he could help if it did all turn sour.

"You're not coming without me." Said Martha.

"Wouldn't dream of it." He nodded.

Outside, a small crowd of troops in gas masks were distributing weapons from several crated that had been helicoptered in. Mace took one of the assault rifles and showed it to the Doctor. "The latest firing stock. What do you think Doctor?"

"Are you my mummy?" He said through his gas mask.

"Doctor, please pay attention. The bullets have a rad steel coating. No copper. It should overcome the cordolaine signal. And armour piercing rounds, designed to take out Daleks."

The Doctor wasn't satisfied. "But the Sontarans have got lasers! You can't even see in this fog. The night vision won't work!"

"Thank you Doctor. Thank you for your lack of faith. But this time, I'm not listening!" Having had about enough of the Doctor's objections, he pulled off his mask so he could address the troops directly. "Attention, all troops. The Sontarans might think of us as primitive, as does every passing species with an axe to grind. They make a mockery of our weapons, our soldiers, our ideals. But no more. From this point on, it stops. From this point on, the people of Earth fight back, and we show them. We show the warriors of Sontar what the human race can do. Trap One to Hawk Major. Go, go, go."

The group was suddenly caught in a massive rush of wind, as though they were standing in the middle of a wind tunnel. All around them, the air began to clear. Hearing a massive roar from above, they looked up to see a dark shape descending towards them.

"It's the valiant!" The Doctor cried, as the ship came into clearer view.

"UNIT Carrier Ship Valiant reporting for duty, Doctor. With engines strong enough to clear away the fog." Said Mace.

Before long, the air was clear enough that they could breathe easily without the gas masks, as well as see clearly in front of them. They suddenly had an island of clear air in a sea of smog. "That is brilliant!" Laughed the Doctor, suddenly feeling a lot more confident in UNIT.

"Getting a taste for it, are we Doctor?" Said Mace.

"No." He said quickly. "Not a bit of it."

"Trap 1 to Hawk Major. Fire at will."

From beneath the hull of the Vallient, several energy beams shot out and met up, like the laser that had taken out the Sycorax ship, except smaller. The ship fired, taking out the section where they'd estimated the most Sontarans would be.

Seconds later, several soldiers blasted through the main doors with bazookas. The Sontarans in the loading bay quickly turned to cover the breech, shooting the first couple who came through, before exchanging fire with those who took up position around the hole.

But this exchange only lasted a few seconds more before another UNIT rocket took out the wall to their left and another squad rushed through and shot them from the side. The whole mass of troops stormed through and into the corridors.

At the same time, UNIT were blowing a number of other entrances to the factory, while several dozen more slid down from the carrier on ropes, blasting through the roof to ensure that the Sontarans were being attacked from all directions at once.

The Sontarans were no pushovers. Skorr had done his best to ensure that every direction UNIT might attack from was covered, and each individual deployment would fight to the death. But once UNIT had overrun a few of them. They rapidly worked together to outmanoeuvre the slower, less numerous Sontarans.

But they fought on anyway. Hurrying down the north corridor to meet the UNIT team that had made a breach nearby, Skorr and two of his men met two soldiers taking up positions just round the corner. They emptied their magazines on Skorr's men. Fortunately, their bodies shielded him and he gunned the soldiers down before they had time to reload.

"This is more like it!" He laughed. "The honour! The glory!"

Amidst all the chaos, the Colonel strode among the troops barking orders. "East and north secure. Doctor, this way."

The Doctor, meanwhile was talking on his phone. "Hold on Donna, I'm coming." With his other hand, he scanned the area with his sonic.

"Shouldn't we follow the Colonel?" Said Martha, watching the man marching down the corridor to the right.

"Nah, we're a team, you and me. Just like old times. Serious alien tech… This way!" And he rushed down the corridor to the left.

Martha heard her phone beep again and promptly tapped _No_. Looking up, she realised, with a note of alarm, that the Doctor was heading in the direction of the lab and hurried after him.

Using the sonic as a guide, the Doctor led them through the subterranean tunnels and soniced the door open. "No Sontarans down here. They can't resist a battle.

He found the real Martha strapped to a bench on the far side and promptly hurried over to her. "Oh Martha, I am so sorry." He checked her pulse. "Still alive. That's good."

Behind him, there came the sound of a gun cocking. He turned round to find clone-Martha pointing a pistol at him. "Am I supposed to be impressed?"

"Wish you'd carried a gun now?" She grinned.

"Not really."

"I was the one stopping those missiles. All that time." She said proudly.

"I know. The Doctor shrugged. I didn't want them to launch any more than the Sontarans did. Can't have Mace start an interstellar war. You were a triple agent."

"You knew?" Said Martha. "When?"

"About you? Oh, right from the start. Reduced iris contraction, slight thinning of the hair follicles on the left temple. And, frankly, you smell. You might as well have worn a T shirt saying clone. Although, maybe not in front of Captain Jack." As expected, a glimmer of familiarity crossed the clone's face. "You remember him, don't you? Because you've got all her memories. That's why the Sontarans had to protect her, to keep you inside UNIT. Martha Jones is keeping you alive." He pulled the device off Martha's head and the medic jerked into consciousness. At the same time, her clone clutched her chest and collapsed.

The Doctor kicked one Martha's gun away then put a reassuring arm round the other. "It's all right, it's all right, I'm here, I'm here. I've got you, I've got you."

"Doctor!" She said. "There was this thing, Doctor, this alien, with this head!"

He dropped her suddenly as the phone rang again. "Blimey I'm busy. Have you got it yet Donna?"

"Yes, now hurry up!" Said Donna's voice.

"All the blue switches. Flip them up."

Martha, meanwhile was staring in bewilderment at her exact double, which was gasping for air and clutching a pillar for support.

* * *

Upstairs, the battle was winding down. Most of the Sontarans had been overwhelmed by sheer numbers. Those that hadn't fought on in isolated pockets.

Mace found one of them in the north corridor, walking in the opposite direction. "You will face me sir!"

Skorr heard his shout and spun round, raising his gun. But Mace fired three shots through him before he got a chance. "Wonderful." Skorr sighed as he closed his eyes.

* * *

As the Doctor was lay in the teleport pod, reconnecting everything, Martha pulled on his coat and tentatively reached out to help her clone, who was dying on the floor.

"Don't touch me!" The other Martha shouted, batting her hand away.

"It's not my fault. The Sontarans created you, but you had all my memories."

The clone relaxed slightly. "You've got a brother, sister, mother and father."

"Yes. And if you don't help, they're all going to die."

"You love them." It took a lot of effort not to say I. Though she'd tried to remind herself that none of the people Martha knew were her family. She felt as though they were.

"Tell us about the gas!" Shouted the Doctor.

"He's the enemy!" Shouted the clone.

"Then tell me." Said Martha. "It's not just poison, what's it for? Martha, please!"

"Caesofine concentrate. It's one part of Bosteen, two parts Probic five." She said at last.

"Clone feed." The Doctor slapped his forehead. "It's clone feed!"

"What's clone feed?" Said the human Martha.

"Like amniotic fluid for Sontarans. That's why they're not invading. They're converting the atmosphere, changing the planet into a clone world. Earth becomes a great big hatchery. Because the Sontarans are clones, that's how they reproduce. Give them a planet this big, they'll create billions of new soldiers. The gas isn't poison, it's food."

"My heart." The clone gasped. "It's getting slower."

"There's nothing I can do." Said Martha.

"In your mind, you've got so many plans. There's so much that you want to do."

"And I will. Never do tomorrow what you can do today, my mum says, because…"

"Because you never know how long you've got." The clone finished for her. "Martha Jones. So much life." With one final gasp, she died.

Martha gently pried her engagement ring off the other Martha's finger.

* * *

"Doc-tor." Donna hissed. "Blue switches done." She heard footsteps behind her and spun round. "But they've found me."

The guard raised its gun in her direction, but then a blue light enveloped her and his image faded to be replaced with the Doctor, waving a sonic at the teleport pod.

"Did I ever mention how much I hate you?" She shouted, running into his arms.

"Hold on!" Shouted the Doctor. "I need to bring the TARDIS down." He soniced some more controls and a readout told him that the TARDIS was back in the alleyway where he'd left it.

"Right then." Announced the Doctor. "Martha, you coning?"

Martha couldn't bring herself to strip her other self's body. But she would need her IDs and phone. "What about this launch thing?" She said, as it flashed up again.

"Just keep hitting _No._" Said the Doctor.

Martha did just that as she made her way over.

Donna, meanwhile was looking between the two Marthas with a sense of bewilderment. "There's… two of them."

"Yeah… Long story." Said the Doctor. "So, the old team back together. Well the new team. The new old team…" He hit some buttons on the teleport's keypad.

"We're not going back on that ship!" Cried Donna.

"No. I just need this to get us to…" He activated it. The room faded around them, to be replaced by... "…the Rattigan Academy. Owned by…"

The moment Luke had heard the pod powering up again, he'd hurried across the room and taken aim at it, expecting Sontarans. When it turned out to be the Doctor and his companions he hurried forward. "Don't tell anyone what I did! It wasn't my fault, the Sontarans lied to me, they…"

The Doctor idly snatched his gun and tossed it aside. "If I see one more gun…"

He strode out the room. Martha and Donna looked Luke up and down for a few moments then went after the Doctor, idly chatting.

"You know, that coat sort of works."

"I feel like a kid in my dad's clothes."

"Oh well, if you're calling him dad, you're definitely getting over him."

Behind them, Luke was holding back further tears.

* * *

"Human female on board." The guard reported. "It can only be the Doctor's work. Now all the teleports are deadlocked open."

"No matter." Said Staal. "Increase converters to maximum." He went to the viewport and stared down at an Earth that now resembled a grey gas dwarf more than anything else. "Behold the start of a new clone world!"

* * *

The air in the major cities now consisted mostly of toxic smoke. Looking out the windows, Wilf could see nothing but darkness, with the smoke blocking the sun. Even most of the house was overrun now. He and Sylvia had withdrawn to the one room which seemed to be sealed from the outside, but gas was still seeping in round the door, no matter how many damp sheets they piled against the door. If the Doctor was going to do something, it would have to be soon.


	8. Scorched Earth

**Chapter 8: Scorched Earth**

"Prepare to launch clone pods." Said Staal. "We shall breed across the Earth, for the glory of Sontar!"

* * *

The Doctor dashed around the main lab at the Academy, hurriedly assembling a device that looked like some futuristic mortar. Explaining everything to his companions as he went. "...that's why the Sontarans had to stop the missiles. They were holding back. Because caesofine gas is volatile, that's why they had to use you to stop the nuclear attack. Ground to air engagement could spark off the whole thing."

"What, like set fire to the atmosphere?" Said Martha.

"Yeah. They need all the gas intact to breed their clone army. And all the time we had Luke here in his dream factory. Planning a little trip, were we?"

Luke was standing at the back of the group, looking sheepish. "They promised me a new world."

"You were building equipment, ready to terraform El Mondo Luko so that humans could live there and breathe the air with this atmospheric converter." He hit some buttons and the device powered up, lighting up with a red glow. The Doctor slung it over his shoulder and hurried outside.

By now, even the countryside wasn't safe. Huge wisps of the Sontaran gas were drifting here and there, carried by the wind. They hung around the group's ankles as they rushed through the flowerbeds. In the distance, Donna spotted an enormous white blob. "That's London! But you can't even see it. My whole family's there."

The Doctor placed the converter down and adjusted some settings on the side.

"Hold on." Said Martha. "You said the atmosphere would ignite."

"Yeah, I did, didn't I." Said the Doctor. He hit the big red button and a ball of red light shot up into the sky, through the clouds. There came a flash from above, followed by a heavy rumbling, followed by the clouds being drawn in from all around the area he'd shot. "Please, please, please." The Doctor muttered, hoping he hadn't made a mistake.

Finally, a wall of fire penetrated the cloud layer, drawing all the gas from the ground as it burnt and rapidly spreading outwards.

* * *

"General Staal." Said an operative. "What's happening?"

Staal watched in alarm as a blanket of flames spread across the planet below, starting in the British Isles and radiating rapidly across continents. The whole Earth was covered in a few seconds.

* * *

Seconds later, the sky overhead began to clear, leaving behind nothing but clear blue skies. The flames passed too quickly to catch on most of the taller buildings. Though there were fires here and there, especially at high altitudes, the population at large was too happy that they'd been saved from chocking to death to care.

Those who weren't chipping in to fight the fires cheered with joy. So elated was Captain Price that she seized the moment and kissed the Colonel. Pulling away, she was disappointed to see a startled look on his face, but that was followed by the twinges of a smile.

* * *

Luke too was leaping for joy. "He did it. He's a genius."

But then they noticed that the Doctor wasn't smiling. "Now we're in trouble."

* * *

The Sontaran plan had failed. There wasn't enough power left in the ATMOS devices to trigger the conversion again. But it is not in the Sontaran nature to expect defeat, and the warship was rapidly readying itself for a full assault. The humans may have got lucky when battling for the factory, but they could do nothing against a full spatial bombardment, which would reduce their cities to dust, and leave what remained too disorganised to resist the advance of their landing parties.

* * *

The Doctor stepped back into the teleport pod, with the converter under his arm. "Right. So, Donna, thank you for everything. Martha, you too. Oh, so many times. Luke, do something clever with your life."

"You're saying goodbye?" Said Donna.

"Sontarans are never defeated. They'll be getting ready for war. And, well, you know, I've recalibrated this for Sontaran air, so..."

"You're going to kill them." Martha finished.

"You'll kill yourself!" Donna cried.

"Just send that thing up on it's own." Said Martha. "I don't know, put it on a delay."

"I can't." Said the Doctor.

"Why not?"

"I have to give them a choice." He hit a button and vanished. The girls silently cursed his sense of reason. Luke just stood staring, the gears turning in his head as he pondered what was left for him in either eventuality.

* * *

The Sontarans looked positively pleased to see him arrive on the bridge at the moment of their triumph. The Doctor grabbed the control panel and stood so that there was a good chance he'd fall on the button if they shot him. "General Staal, you know what this is."

Staal nodded.

"But there is another way. You can leave. High command need never know what happened here."

"Your stratagem would be wise if the Sontarans feared death." Said Staal. "At arms."

Behind him, the computer was readying the main gun, drawing up a list of the highest priority cities to destroy.

"I'll do Staal. If it saves the Earth."

"A warrior doesn't talk, he acts!" Shouted Staal.

"I'm giving you a chance. A chance to leave."

"And miss the crowning triumph?"

"All weapons targeting Earth sir." Said an operative. "Firing in 20."

"I'm warning you Staal!" Shouted the Doctor.

"And I salute you." Said Staal. Take aim." But he decided to wait a while. Let him see them bombard his precious Earth, then kill him.

"You shoot me, I'm still going to press this! You'll die Staal."

"Knowing that you die also. For the glory of Sontar. Sontar-ha! Sontar-ha! Sontar-ha!"

His men joined in. "Sontar-ha! Sontar-ha! Sontar-ha!"

The Doctor stared at them in despair. How do you threaten a species that fears nothing? Standing with his hand over the button, he just couldn't bring himself to press it. He didn't know if it was the fear of death, the fear of killing the Sontarans or just the simple psychological impact of having to take life with your own hands.

* * *

Down in the Academy, Martha and Donna were sat with their heads in their hands. But Luke had come to a decision and was quickly adjusting some cables in the teleport.

"What are you doing?" Said Donna.

"Something clever." He shrugged, and hit the button.

* * *

The Doctor mentally psyched himself up. Knowing he had no choice didn't make this easier.

"10, 9, 8," said the operative.

"Sontar-ha! Sontar-ha! Sontar-ha!"

"7, 6, 5,"

"Sontar-ha! Sontar-ha! Sontar-ha!"

Suddenly, the Doctor vanished and Luke appeared in his place, catching the control panel as it fell. For the first time, Staal looked worried.

"4, 3, 2..."

""Sontar! Ha!" Luke roared and slammed down on the button with all his fury at the species that had made a fool of him.

A huge ball of fire shot out from the machine. In the contained environment, the flames had nowhere to go. They wrecked each and every control system and set off a chain reaction throughout the ship. The vacuum shields and the flow regulators malfunctioned in quick succession and a series of explosion went off, blasting the ship to smithereens.

* * *

The Doctor emerged, gasping from the teleport. The hijacked controls had made the journey rougher than he'd have liked.

Martha hurried up and comfortingly grasped his left arm. Donna hurried up and gave his right arm a good whack for putting her through that. But then she rubbed the spot she'd whacked soothingly.

* * *

The Doctor had stayed around for a couple of days while he helped Martha take a leave of absence, on grounds of replication-related trauma (apparently, that happened often enough that the forms had a box you could tick for it.) As well as reassigning her paperwork (a skill he'd got very good at during his time there).

It also gave Donna a chance to make sure her family were alright. She sat with her Granddad, listening to the urban sound that she had never known to be so quiet. Though anyone who had had an ATMOS car had removed the devices now, they were still reluctant to get back in them.

The door came open, as her mother returned from the supermarket, having walked there and back, carrying everything in a rucksack. "The streets are half empty. People still aren't driving. There's kids on bikes all over the place. It's wonderful. Unpack that lot, I'm going to see if Suzette's all right."

Donna had come to her decision. Her mother would probably have throttled the Doctor if she'd seen what she'd been through on that ship. But how to explain it to Wilf?

Fortunately, she didn't need to. "I won't tell her." He said. "Best not. Just keep it as our little secret, eh?"

"Yeah."

"And you go with him, that wonderful Doctor. You go and see the stars, and then... bring a bit of them back for your old Gramps."

She stood up and hugged him. "Love you." She said, before leaving.

* * *

Donna stepped into the TARDIS, to find Martha, who'd come to see them off. "They ok?" Said Martha.

"You know. Same old." Said Donna. "So... You coming with us? We're not exactly short of space."

Martha looked lovingly round the console room. "Oh, I have missed this. But, you know, I'm good here. And I'm better for having been away. Besides..." She held up her engagement ring. "Someone needs me. Forget the universe. I've got a great big life of my own right here!" She made her way to the doors, only for them to slam shut of their own accord. This was followed by a horrible lurch, which threw them all to the floor as the engines started roaring.

"Don't you dare!" Shouted Martha.

The Doctor hauled himself up the console and pulled the scanner round. "It's not me! I didn't touch anything! We're in flight!"

The floor rocked back and forth like the world's most rapid traverse earthquake.

"Where are we going?" Shouted Donna.

"I don't know!" Shouted the Doctor. "The TARDIS has a mind of its own!"

"Take me home!" Shouted Martha. "You take me home right now!"

* * *

**Author's notes: And with David Tennant off to meet his future wife, this is where we leave.**

**Next time: Utopia/The Sound Of Drums/The Last Of The timelords**


End file.
